Multicenter study of genetic abnormalities associated with severe oligospermia and non-obstructive azoospermia

Objective * Chong Xie, Xiangfeng Chen, and Yulin Liu contributed equally to this work. Genetic defects are identified in nearly 20% of infertile males. Determining the frequency and types of major genetic abnormalities in severe male infertility helps inform appropriate genetic counseling before assisted reproductive techniques. Methods Cytogenetic results of 912 patients with non-obstructive azoospermia (NOA) and severe oligozoospermia (SOS) in Eastern China were reviewed in this multicenter study from January 2011 to December 2015. Controls were 215 normozoospermic men with offspring. Results Among all patients, 22.6% (206/912) had genetic abnormalities, including 27.3% (146/534) of NOA patients and 15.9% (60/378) of SOS patients. Chromosomal abnormalities (all autosomal) were detected in only 1.9% (4 /215) of controls. In NOA patients, sex chromosomal abnormalities were identified in 25.8% (138/534), of which 8% (43/534) had a 47,XXY karyotype or its mosaic; higher than the SOS group prevalence (1.1%; 4/378). The incidence of Y chromosome microdeletions was lower in the SOS group (13.2%; 50/378) than in the NOA group (17.8%; 95/534). Conclusions The high prevalence of genetic abnormalities in our study indicates the importance of routine genetic testing in severe male infertility diagnosis. This may help determine the choice of assisted reproductive technique and allow specific pre-implantation genetic testing to minimize the risk of transmitting genetic defects.